Since Smuxi is open-source and free software it is developed by volunteers. Without these volunteers Smuxi wouldn't exist. If you have some spare time and want to give something back then you can contribute to Smuxi in many different ways. You don't have to be a programmer and neither need to become one to contribute!
If you run into an issue or miss something that feels important to you and possibly others then you can help by reporting issues or requesting features using Smuxi's issue tracker. All you need to do is to create an account here once. Your account is not usable right away because the account needs to be approved first. You don't need to specify your real name if you don't like, but don't use names that look like you are a spammer ;). After your account was approved (usually within a day, if not poking meebey on IRC can help) you are good to create your first bug report or feature request from here. If you are not sure if you do the right thing in the tracker, don't hesitate to submit it anyhow. We are thankful for every feedback you provide and tune the ticket when needed.
You like Smuxi and know people who suffer from bad messaging apps? Do them a favor and tell them about how Smuxi works for you. They possibly would have a better messaging experience by using Smuxi. Smuxi is not the right app for everyone needs of course, but one can only judge this by trying or considering it at least! So if someone rants about his volatile IRC client, the horrible Twitter web app or the infamous Facebook web chat, point them to https://smuxi.im
One important step before a new Smuxi version is released, is to test the new version before the final release with the release announcement. Why? Assume newly written code would be released without good testing. This could lead to nightmares of every software like broken features or even application crashes! The only way to prevent this is by continuously testing development versions or at least by testing release candidate before the final release.
If you run into an issue in the new version it is important to report the issue using Smuxi's bug tracker mentioned in the Provide Feedback section above.
So where do I get release candidates? Release candidates are usually announced on the #smuxi-devel @ freenode IRC channel, Smuxi planet feed (RSS version) and inside the Smuxi itself in the Smuxi home chat showing Smuxi news. You can also seek for release candidates in this web directory. All release candidates have a ~rc suffix in their filename.
OK, release candidates are good, but where do I get the still bleeding stuff? Daily development builds/snapshots of Smuxi are currently only provided as source code via Git, binary packages for Debian and Ubuntu or only by request for Mac OS X and Windows. More details can be found in the running from git documentation.
Smuxi is using the Transifex translation project to coordinate and maintain the translations. If you want to submit or update translations, just visit the Smuxi project on Transifex here. If the language is not present yet simply request a language team and we will approve it. After your team was approved you can start translating Smuxi to a new language.
How does Transifex work? Take a look at this Transifex guide on YouTube.
Which languages are already translated and which need work?
You knew this was coming! Obviously you can also contribute by writing code. Smuxi is written in sexy C# and a nice Smuxi hacking how-to can be found over here. For inspiration what to hack on, check out the bug reports and feature requests. Here you can also find a list of "low hanging fruits" to get familiar with Smuxi's code base.